The breasts contain glandular tissues surrounded by fat, connective tissue, blood vessels and lymph nodes. Glandular tissue within the breast responds to circulating hormones that allow for surges in breast growth during puberty and pregnancy in females. Male breast growth, also called gynecomastia, occurs when males grow firm breasts rich in glandular tissue that are distinct from pectoral fatty deposits observed in some obese men. Gynecomastia often indicates a physiological abnormality that stems from an underlying disorder.
Drug Use
In some cases, gynecomastia may develop as a result of lifestyle factors, such as drug abuse. Male breast growth can occur as a result of exposure to estrogen or low levels of testosterone, so drug use that modifies hormone levels can cause male breast growth. Prescription medications such as digoxin, spironolactone or cimetidine may cause gynecomastia, according to the New York University Langone Medical Center. Regular marijuana use can also enhance male breast growth, and anabolic steroids can cause male breast growth once a patient stops using the drug. Men suffering from gynecomastia should disclose any medication or drug use to a physician to investigate the cause of their condition.
Hormone-Producing Tumors
Male breast growth may also develop as a result of hormone-producing tumors, leading to hormone imbalances. A number of glands throughout the body, called endocrine glands, produce and secrete a wide range of hormones that signal to a number of tissues, including breast tissue. Among these glands are the testicles, which produce and secrete a number of hormones such as testosterone and estrogen. Testicular tumors can lead to an increase in estrogen secretion and a high level of estrogen in the bloodstream, according to the UCLA Department of Medicine. The excess estrogen signals to breast cells and promotes cell division and breast growth. Treating the underlying tumor with surgery, chemotherapy or radiation therapy helps restore normal hormone production to treat the cause of gynecomastia.
Cancer Therapies
Hormone imbalances that cause gynecomastia may also develop as a result of cancer therapy. Some forms of cancer, such as prostate cancer, worsen upon exposure to androgens like testosterone. As a result, patients with prostate cancer may receive treatment to lower testosterone levels or prevent cells within the body from responding to circulating testosterone. Dr. Glenn D. Braunstein of Cedars-Sinai Medical Center reports that around 75 percent of men receiving anti-androgen therapy develop gynecomastia as a result of hormone imbalances associated with treatment. Men suffering from gynecomastia may explore other prostate cancer therapies, such as radiation, to avoid hormone imbalances that promote breast growth.
